A wide-ranging program that would give consumers turning in old clunkers cash vouchers worth up to $5,000 to buy new, more fuel-efficient vehicles was introduced this week in Congress.

The bill aims to boost car sales in the midst of the recession, help struggling consumers buy new cars and cut pollution by taking some of the oldest, dirtiest cars off the road.

An earlier version of so-called “cash for clunkers” incentives ran into union opposition that it could end up favoring imports. To avoid that problem, this new measure awards an extra $1,000 for vehicles assembled in the United States.

The bill proposes giving consumers vouchers to buy new, more fuel-efficient vehicles in exchange for turning in vehicles at least eight years old. The program is dubbed the Consumer Assistance to Recycle and Save bill, or CARS Act.

Sutton noted that 60 percent of vehicles in the United States are old enough to qualify. The bill would award higher vouchers for vehicles assembled in North America — up to $5,000 — versus up to $4,000 vouchers for vehicles assembled outside North America, and would not apply at all to vehicles made outside North America. The proposal was endorsed Tuesday by Detroit’s Big Three automakers and the UAW.

To qualify, consumers would have to buy a vehicle more fuel-efficient than their current car or truck. The new vehicles also would have to be priced at $35,000 or less.

The bill would offer a $7,500 cash voucher starting in 2010 for plug-in electric hybrids that get 100 mpg or more. Car owners also could turn in their vehicles in exchange for a mass transit voucher worth up to $3,000.

GM chairman and CEO Rick Wagoner told reporters in Washington Tuesday that a bill to offer cash for older cars — often dubbed “cash for clunkers” — could benefit the auto industry.

“These kinds of programs can have a huge impact,” Wagoner said, saying it could boost consumer confidence. “It would be very helpful to have something like that here in the United States.”